Growth and the composition and transport of carbohydrate in compatible and incompatible peach/plum grafts

The growth of scions and rootstocks of compatible (Prunus persica L. Batsch cv. Springtime/Prunus cerasifera L. Ehrh. cv. myrobolan P2032) and incompatible (Prunus persica L. Batsch cv. Springtime/Prunus cerasifera L. Ehrh. cv. myrobolan P18) peach/plum grafts were compared. The composition of soluble carbohydrates in phloem and cortical tissues of both peach/plum grafts and ungrafted plums and the translocation of these compounds across the union of grafted plants were examined. Sorbitol and sucrose were the dominant sugars in the phloem and cortical tissues of plum. A cyanogenic glycoside, prunasin, was present in peach tissues in amounts equivalent to those of sorbitol or sucrose, whereas only small amounts of prunasin were detected in plum tissues. The concentration of prunasin was significantly higher in the phloem of the P18 rootstock of the incompatible graft. Sorbitol was the only sugar significantly depleted in rootstock tissues of the incompatible graft when the first foliar symptoms of graft incompatibility became evident. Translocation studies with 1-(14)C-deoxyglucose showed that the relative distribution of radioactivity across the graft union was similar in both compatible and incompatible grafts. However, the total amount of radioactivity translocated across the incompatible graft was less than one-third of that translocated across the compatible graft. The results are consistent with the hypothesis of a progressive poisoning of the root system in the incompatible graft by a compound synthesized in peach foliage. The role of prunasin as a possible candidate is discussed.     

Carbon and nitrogen partitioning in peach/plum grafts

Modifications in root-shoot relationships induced by graft incompatibility were studied in peach/plum graft combinations by means of carbohydrate and nitrogen analyses and isotope labeling. Mobilization of stored carbon, phloem transport of carbon, and mobilization, assimilation and distribution of nitrogen were studied in one compatible peach/plum graft (Prunus persica L. Batsch cv. springtime grafted on Prunus cerasifera L. Ehrh cv. myrobalan P 2032) and one incompatible graft (Prunus persica L. Batsch cv. Springtime grafted on Prunus cerasifera L. Ehrh cv. myrobalan P 18) for 89 days after grafting. Carbon and nitrogen reserves were mobilized in the rootstock in both graft combinations during the first 78 days following grafting. After that, sorbitol concentration was lower in the roots of the incompatible graft than in the roots of the compatible graft, whereas soluble sugars and starch accumulated in the peach scion of the incompatible graft. In both graft types, carbon was allocated mainly to the scion. Labeling with (13)CO(2) from 78 to 81 days after grafting showed that carbon partitioning among the different plant organs was only slightly affected by graft incompatibility. Carbohydrate concentrations provided indirect evidence that carbon transfer to the roots was hindered in the incompatible graft. Labeling with (15)NO(3) showed that nitrogen distribution and the rate of nitrogen assimilation were similar in the two graft combinations from 57 to 78 days after grafting. Nitrogen assimilation in the incompatible graft ceased 78 days after grafting, whereas it continued in the compatible graft.     

Localized graft incompatibility in pear/quince (Pyrus communis/Cydonia oblonga) combinations: multivariate analysis of histological data from 5-month-old grafts

To characterize the structural events associated with incompatibility of graft development, we conducted a histological study of compatible and incompatible pear/pear and pear/quince grafts that had been grown for five months in a greenhouse. Multivariate analysis of histological data describing the structure of the graft union allowed us to discriminate between compatible and incompatible combinations before either macroscopic examination or qualitative microscopic examination differences between graft combinations became evident. The histological variables responsible for the discrimination between incompatible and compatible unions were related to three typical symptoms of graft incompatibility: bark discontinuity, which was the main feature; cambial dysfunction; and accumulation of starch in the scion. Little cell necrosis was observed at the interface of incompatible grafts at the 5-month stage of graft development. Multivariate analysis of histological data provides a new tool for studying early structural events resulting from the graft incompatibility response and for diagnosing early graft incompatibility.     

Clonal propagation of Leucaena by single bud splice grafting with a new grafting tool,and by modified veneer crown grafting

A simple tool called the graft guide, and its use with a new grafting technique called the single-bud splice (SBS) graft is described. The graft guide assures precise complementary rootstock and scion cuts, and thus ensures good cambial contact necessary for graft union formation. The use of this tool to graft small (3–15 mm) vegetative shoots of Leucaena species and hybrids is illustrated. An overall grafting success rate of 72% was achieved using this technique for several leucaenas. An additional modified veneer grafting technique for use when rootstock is larger in diameter than the scion, achieved 73% success. Graft compatibility results from 961 grafts between scions of 15 Leucaena species and three interspecific hybrids, and rootstocks of two species are presented. Of the 48 scion/rootstock combinations attempted, 43 (90%) were successful.     

Rootstock effects in grafted conifers: A review

The literature on rootstock effects (on scions) in conifers was reviewed, specifically: graft success, compatibility, size, reproduction, phenology, crown and needle characters, mineral contents, organic compounds, water relations, disease resistance and wood properties. Scions usually had higher graft success and less incompatibility on more closely related rootstocks although there were exceptions. Even intergeneric grafts have succeeded on occasion. Although there were marked rootstock effects on growth and reproduction, the effects did not follow a pattern with increasing relationship. It is also likely that some crown characters and the nutrient content of scions can be manipulated by the use of rootstocks. For many characters, a specific rootstock may give a desired result only for a limited number of scion types (species, cultivars or clones). With some exceptions, the review shows that the subject has not been comprehensively studied. Many of the studies were either short-term, inadequately replicated, or poorly designed to allow firm conclusions about rootstock effects. The physiological and biochemical mechanisms, which cause the changes seen in morphology, are not well understood. Further research and more comprehensive study of rootstock effects on scion biology are recommended.     

抗病和感病泡桐无性系组培苗对嫁接传染植原体的不同反应

用感染了植原体并表现典型丛枝症状的组培苗作接穗或砧木，在无杂菌条件下嫁接７个表现不同田间抗性的无性系健康组培苗，并用ＤＡＰＩ荧光显微镜和１６ＳｒＲＮＡ基因扩增（ＰＣＲ）技术检验嫁接传病效果。Ｃ１２５和ＸｕＨ表现出较强的特异性接种诱发坏死反应，ＺＨ和Ｔ３５０２８坏死反应中等，ＱＬＭ、Ｃ０２０和Ｃ１６１的坏死反应较弱。培养基中添加植物生长调节剂（６ＢＡ或ＮＡＡ）可降低坏死程度，提高嫁接成功率，水杨酸处理或去掉健株砧木叶片和根系皆加重坏死反应程度。用病接穗嫁接抗病的ＱＬＭ无性系时，用ＰＣＲ检测到侵染砧木的植原体，但未表现丛枝症状，而将此无性系健康接穗嫁接到丛枝病砧木上时可诱致典型丛枝症状，从而表现出与根系和成熟叶相关的抗性反应。除Ｃ１２５外，其余６个无性系皆被嫁接传染，其继代培养表现出差异不显著的丛枝症状，其韧皮部金黄色自发荧光随着症状的加重而累积，也与抗病性有一定的联系。     

锥栗芽苗砧嫁接技术

为了提高锥栗芽苗砧嫁接成活率,以野生锥栗种子作为砧木,以‘华栗3号’当年生营养枝作为接穗,采用嫩枝劈接法,研究4个嫁接时期(4月20日、5月10日、6月1日、7月10日)、5种日龄砧木(20、30、45、60、90 d)和封口材料及封口方式(铝箔、嫁接膜封顶、嫁接膜不封顶)对锥栗芽苗砧嫁接成活率的影响。结果表明:封口材料与封口方式对嫁接成活率存在较大影响,不同的封口材料与封口方式处理的嫁接苗成活率从高到低依次为:嫁接膜封顶、铝箔、嫁接膜不封顶;6月1日为最佳嫁接时期,嫁接膜封顶处理的嫁接成活率达64.00%;砧木年龄过小(20 d)或过大(90 d)均对嫁接成活不利,当砧木日龄为45 d时,嫁接成活率最高,为69.33%。     

Open-pollinated, interspecific F1 hybrid seed orchards of Leucaena: I. Rootstock effects

Seed orchards of Leucaena were established at two experimental sites in Hawaii to produce either triploid or tetraploid interspecific hybrid seed by interplanting clonal self incompatible diploid (L. diversifolia, L. esculenta) or tetraploid (L. pallida) species with self- compatible L. leucocephala lines and the F1 hybrid of L. diversifolia (2n = 4x) × L. leucocephala. The seed parents were grafted onto three seedling rootstocks (L. diversifolia (2n = 4x), shrubby L. leucocephala, and giant L. leucocephala) to compare rootstock effects on scion growth. This paper reports on the effects of rootstock on scion growth during the first year based on total truck cross sectional area, height growth, and crown habit. In the triploid seed orchard, rootstock significantly affected the growth of four of the six clones, while in the tetraploid orchard the growth of two of the five clones was significantly affected by rootstock. Crown habit was independent of rootstock. Our study suggests that rootstock effects depend on the specific scion and rootstock combination, and site. This revised version was published online in June 2006 with corrections to the Cover Date.     

Growth patterns and morphology of fine roots of size-controlling and invigorating peach rootstocks

We compared growth patterns and morphology of fine roots of size-controlling and invigorating peach (Prunus persica (L.) Batsch) rootstocks. Peach trees were grafted on five rootstocks: a vigorous control (Nemaguard), three intermediate vigor rootstocks (K119-50, P30-135 and Hiawatha), and a semi-dwarfing rootstock (K146-43). Minirhizotron tubes were installed at the base of trees on each rootstock and root images captured with a minirhizotron digital camera system. Number, visible length, and diameter of new roots were recorded at fixed soil depths from April 19, 2000 to December 19, 2001. Root diameter, specific root length, root tissue density and root length density were also measured periodically for each rootstock on roots collected from in-growth cores. Rootstocks had similar seasonal patterns of new root production. Fine root production was lowest in winter and appeared to decline during the final stages of fruit growth. A rootstock with almond in its genetic background (K119-50) produced the greatest quantity of fine roots and had the greatest number of new roots below 69 cm, whereas there were no differences among the other four rootstocks in the total number of roots produced. Rootstock K146-43 had thicker fine roots than the other rootstocks. Independent of rootstock, fine roots produced during spring had greater specific root length than those produced later in the season. The seasonal pattern of fine root production did not appear to be associated with the previously reported effects of these dwarfing rootstocks on shoot growth and stem water potential early in the growing season.     

景阳薄壳核桃枝接大田育苗试验研究

笔者采用子苗砧、切接等4种方法开展核桃大田嫁接育苗试验表明:4种方法间存在显著性差异,其中以子苗砧嫁接成活率最高达81%.同时采用切接方法于不同时期开展核桃嫁接试验,结果表明在建始县低山区以3月中、下旬为最佳嫁接时期.     

核桃芽接愈合的组织学机制

【目的】通过对核桃芽接愈合过程的组织学观察,研究不同嫁接时期砧穗在愈伤组织形成、增殖和输导组织连接过程中的组织学变化机制,旨在为核桃和其他木本植物嫁接提供理论指导。【方法】以12年生核桃品种‘香玲’半木质化新梢中部芽片为接穗,2年生本地核桃实生苗为砧木,采用方块芽接法分别于砧木萌芽后40~47天和100~107天2个时间进行芽接试验,采用本课题组建立的非均质化材料切片方法对芽接愈合过程进行组织学观察。【结果】核桃萌芽后40~47天的砧穗愈合方式与前人报道一致,即形成层细胞在嫁接体愈合过程中起主导作用,愈合过程中主要组织学变化包括:隔离层的产生(3天)→砧穗形成层细胞分化产生愈伤组织(4天)→愈伤组织连接(6天)→砧穗原有形成层的修复与连接(12天),完成愈合需要12~15天,成活率达95.6%。而在萌芽后100~107天的砧穗愈合过程中,发现了与上述常规愈合不同的嫁接愈合新方式。此过程中木射线细胞起主导作用,愈合过程依次历经隔离层的产生(3天)→木射线细胞分化产生愈伤组织(4天)→砧穗愈伤组织连接(9天)→导管分化形成(15天)→新的形成层产生以及木射线的连接(25天),需要25~30天才能完成愈合,成活率为61.7%;在木射线细胞主导的砧穗愈合过程中砧木一侧的隔离层要先于接穗发生溶解,在砧穗愈伤组织完成连接时消失,而接穗表面隔离层在愈伤组织分化时依然存在,直至新的形成层产生后才完全溶解消失。【结论】核桃芽接过程中,除了常见的由形成层细胞主导的砧穗愈合方式外,还存在由木射线细胞主导的砧穗木质部的愈合新方式,木射线细胞脱分化产生愈伤组织,并进一步分化出导管、形成层和木射线等组织完成最终的砧穗连接;在此过程中愈伤组织主要来自于砧木木射线细胞且砧木隔离层要先于接穗发生溶解。     

核桃优良砧木选育的研究

笔者通过对6种核桃砧木苗生长状况,嫁接核桃良种后的接芽萌发期、嫁接成活率、接芽生长量等内容的研究。结果表明：1）美国黑核桃播种后,种子出苗率、苗木高生长量、径生长量明显高于核桃本砧,而且根系刨根分析结果显示美国黑核桃根深、强壮。2）美国黑核桃经嫁接良种核桃试验,比核桃本砧嫁接成活率高、接芽萌发早,且生长速度快;嫁接伤口愈合良好,亲和力强。因此认为,美国黑核桃可作为优良砧木用于进一步试验。     

金花茶嫁接繁殖砧木亲和力试验

针对影响金花茶嫁接愈合成活的主要因素之一——砧穗亲和力,进行了以多个油茶物种为砧木的金花茶嫁接快繁砧穗亲和力的试验研究。结果表明:参试的7种砧木均有亲和力,其中以博白大果油茶和义安油茶为砧木的亲和力为最高,其次为普通油茶;茶叶树虽然有亲和力,嫁接成活率最高可达73.3%,但其表现后期不亲和,不宜用作金花茶的砧木。     

樟树观赏新品种‘涌金’嫁接试验

采用1年生、3年生、5年生樟树小苗作砧木,‘涌金’2年生春枝、夏枝、秋枝及3年生秋枝作接穗,分别于2月、3月、4月、9月在离地5、50、100 cm处截干劈接,进行‘涌金’嫁接育苗试验.结果表明:在综合考虑嫁接成活率、生长量及景观效果等因素下,‘涌金’嫁接最为有利的模式为:3月,选用3年生或以上樟树小苗作砧木,2年生的春枝、夏枝作接穗,在离地50 cm以上部位截干劈接.     

Factors influencing in vivo and in vitro micrografting of sandalwood (Santalum album L.): an endangered tree species

In vivo micrografting of Santalum album was achieved (50%) by grafting 4- to 5-cm-long scions, collected from a candidate plus tree (CPT) of 50–60 years of age, onto 90-day-old nursery-grown rootstock. Scion size, rootstock age, and scion collection season were found to influence graft success. Grafted plants were incubated under greenhouse conditions for 6–8 weeks during the graft union process. In vitro micrografts were achieved by placing 1- to 2-cm-long scions derived from nodal shoot segments (collected from CPT) onto the hypocotyl of 45-day-old in vitro rootstocks. Use of in vitro grown shoots as a source of scion gave better graft success (60%) than scions collected directly from field-grown trees. In vitro grafting was also influenced by scion size and rootstock age. Under favorable conditions, scions and hypocotyls unite to form complete plants that produced two to four leaves after 6–8 weeks. This is the first report on in vivo and in vitro micrografting of S. album having potential for production of disease-free clonal plants for conservation and improvement targets.     

早实核桃芽接愈伤形成过程扫描电镜观察

为给完善核桃芽接繁育技术提供参考,选用山东地方品种‘鸡爪绵’核桃实生苗为砧木,采用大方块芽接方法嫁接早实核桃品种‘香玲’和‘元林’,利用扫描电镜观测其砧穗组合体愈伤形成和嫁接口愈合过程。结果表明:2个早实核桃品种嫁接愈合过程相似,嫁接后第6天砧穗嫁接体愈合完成。第1天,嫁接口接穗上有愈伤组织细胞产生,同时有少量无机、有机分泌物或晶体;第2天,嫁接口处产生大量愈伤组织细胞,‘香玲’和‘元林’接穗愈伤组织细胞直径分别为17.5~35.0和14.1~33.3μm,‘元林’接穗愈伤细胞数量明显多于‘香玲’;第4天,愈伤细胞延伸分化出明显的愈伤组织,愈伤组织不断分裂;第5天,砧穗愈伤组织相互交叉连接;第6天,接穗和砧木间的维管束已重新连接,嫁接愈合完成。     

The dwarfing mechanism of citrus rootstocks F&A 418 and #23 is related to competition between vegetative and reproductive growth

The annual development of Navelina (Citrus sinensis (L.) Osbeck) trees budded on three hybrid citrus rootstocks was studied. Two rootstocks, named #23 and #24, were obtained from the cross of Troyer citrange (C. sinensis x Poncirus trifoliata (L.) Raf.) x Cleopatra mandarin (C. reshni Hort. ex Tan.). The third rootstock, named F&A 418, came from a cross of Troyer citrange x common mandarin (C. deliciosa Ten.). Rootstocks #23 and F&A 418 are dwarfing rootstocks and reduce the size of the scion by about 75%. Rootstock #24 yields a standard size scion. Major growth differences that influenced tree size were apparent during the first summer after grafting and appeared to be related to fruit productivity, because defruiting the dwarfed scions caused a significant increase in vegetative shoot development, including summer sprouting. The reduced growth of the dwarfed scions was not restored by hormone application, indicating that a hormonal deficiency is unlikely to be the primary reason for scion dwarfing, although differences in gibberellin concentrations were found in actively growing shoots. Leaf photosynthesis was similar in scions on all three rootstocks, but the carbohydrate accumulation in fruits and fibrous roots during the summer sprouting period was significantly greater in the dwarfed trees than in the standard trees. Our results suggest that the dwarfing mechanism induced by the F&A 418 and #23 rootstocks is mediated by enhanced reproductive development and fruit growth, resulting in reduced vegetative development in the summer. Thus, a change in the pattern of assimilate distribution appears to be one of the main components of the dwarfing mechanism.     

蜡杨梅与杨梅种间嫁接及亲缘关系分析

【目的】研究蜡杨梅与杨梅的嫁接亲和性及亲缘关系,为杨梅扩展栽培提供参考。【方法】连续3年在浙江余姚滩涂上(土壤pH8. 01),以蜡杨梅和杨梅为砧木,以4种主栽品种‘荸荠种’‘东魁’‘夏至红’和‘水晶种’为接穗的种间嫁接,并基于SSR对蜡杨梅和杨梅进行亲缘关系鉴定和聚类分析。调查各砧穗组合的嫁接成活率及相关指标。【结果】杨梅砧穗组合的嫁接成活率为:70. 08%～83. 75%,其中‘夏至红’接穗的嫁接成活率最高(81. 98%),‘荸荠种’次之(80. 43%);蜡杨梅砧穗组合的嫁接成活率为27. 51%～38. 29%,其中,‘东魁’接穗的嫁接成活率最高(34. 88%);杨梅砧穗组合的嫁接成活率极显著高于蜡杨梅砧穗组合。不同组合间的T-test显示:蜡杨梅砧穗组合BQ4-6、DK4-6和SJ4-6分别在冠径、干周和植株高度等指标上显著性高于杨梅砧穗组合。6个指标的相关性分析显示:2个砧木群体在连续3年的试验中,嫁接成活率与植株高度和冠径之间均存在显著性正相关,砧木高度与植株高度均呈现显著性负相关。利用127对SSR标记对2个砧木及4个接穗材料进行了多态性检测,聚类分析后分为3个群体,蜡杨梅与杨梅的种间亲缘系数为0. 31,杨梅砧木与‘夏至红’亲缘关系最近,与‘荸荠种’次之;蜡杨梅与‘东魁’亲缘关系最近;与嫁接成活率的表现一致,亲缘关系越近成活率越高。【结论】蜡杨梅砧木与杨梅接穗间存在一定的亲和性,而且更适合生长在碱性土壤中。     

Scion-rootstock interaction affects the physiology and fruit quality of sweet cherry

Water relations, leaf gas exchange, chlorophyll a fluorescence, light canopy transmittance, leaf photosynthetic pigments and metabolites and fruit quality indices of cherry cultivars 'Burlat', 'Summit' and 'Van' growing on five rootstocks with differing size-controlling potentials that decrease in the order: Prunus avium L. > CAB 11E > Maxma 14 > Gisela 5 > Edabriz, were studied during 2002 and 2003. Rootstock genotype affected all physiological parameters. Cherry cultivars grafted on invigorating rootstocks had higher values of midday stem water potential (Psi(MD)), net CO(2) assimilation rate (A), stomatal conductance (g(s)), intercellular CO(2) concentration (C(i)) and maximum photochemical efficiency of photosystem II (PSII) (F(v)/F(m)) than cultivars grafted on dwarfing rootstocks. The Psi(MD) was positively correlated with A, g(s) and C(i). Moreover, A was positively correlated with g(s), and the slopes of the linear regression increased from invigorating to dwarfing rootstocks, indicating a stronger regulation of photosynthesis by stomatal aperture in trees on dwarfing Edabriz and Gisela 5. The effect of rootstock genotype was also statistically significant for leaf photosynthetic pigments, whereas metabolite concentrations and fruit physicochemical characteristics were more dependent on cultivar genotype. Among cultivars, 'Burlat' leaves had the lowest concentrations of photosynthetic pigments, but were richest in total soluble sugars, starch and total phenols. Compared with the other cultivars, 'Summit' had heavier fruits, independent of the rootstock. 'Burlat' cherries were less firm and had lower concentrations of soluble sugars and a lower titratable acidity than 'Van' cherries. Nevertheless, 'Van' cherries had lower lightness, chroma and hue angle, representing redder and darker cherries, compared with 'Summit' fruits. In general, Psi(MD) was positively correlated with fruit mass and A was negatively correlated with lightness and chroma. These results demonstrate that: (1) water relations and photosynthesis of sweet cherry tree are mainly influenced by the rootstock genotype; (2) different physicochemical characteristics observed in cherries of the three cultivars suggest that regulation of fruit quality was mainly dependent on the cultivar genotype, although the different size-controlling rootstocks also had a significant effect.     

降香黄檀嫁接技术研究

Dalbergia odorifera T. Chen is one of the two most precious tree species naturally distributed in China. The grafting techniques of D. odorifera were studied through comparing grafting methods, grafting seasons, rootstock grades as well as scion buds. The results showed that both "scarf joint grafting" and traditional cleft grafting were feasible for stem grafting. The two-bud "scarf joint grafting" got the best survival rate, while the cleft grafting was easy to operate. The best grafting seasons varied in the light of climate. In the warm southwest of Hainan island, the best grafting season was winter when the survival rate could achieve as high as 99.1%. While in Guangzhou, the best grafting season was the end of fall, and the corresponding survival rate was 94.6%. The quality of rootstock as well as scion bud affected the growth of scion bud directly. The growth of grade I buds/grade I rootstocks were 17 times that of grade III buds/grade III rootstocks. The study was beneficial for the preservation of high quality germplasm resources as well as for clone grafting of D. odorifera.